Drawing-board



(No Model.)

J. 1). M GABE. DRAWING BOARD.

No. 467,825. Patented Jan 26, 1 92,

WITNESSES:

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Uwrrnn STATES PATENT OFFICE.

JUNIUS D. MOOABE, OF OORAOPOLIS, PENNSYLVANIA.

DRAWING-BOARD.

SPECIFICATION forming part of Letters Patent No. 467,825, dated January 26, 1892.

Application filed November 19, 1891- Serial No. 412,418. (No model.)

To all whom it may concern.-

Be it known that I, JUNIUS D. MGOABE, of Coraopolis, in the county of Allegheny and State of Pennsylvania, have invented a new and Improved Drawing-Board, of which the following is a full, clear, and exact description.

The object of the invention is to provide a new and improved drawing-board which is simple and durable in construction, arranged to conveniently plot surveys from notes, using either hearings or angles, and which also serves as a revolving drawing-board for different purposes.

The invention consists of a stationary frame provided with a head supporting a quadrant adjacent to the edge of the circular drawingboard mounted to turn on the said frame, and provided at its outer edge at each ninety-degree point with a Vernier reading to minutes.

The invention also consists of certain parts and details and combinations of the same, as will be fully described hereinafter, and then pointed out in the claims.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar letters of reference indicate corresponding parts in all the figures.

Figure 1 is a plan View of the improvement. Fig. 2 is a sectional side elevation of the same on the line 2 2 of Fig. 1. Fig. 3 is an enlarged transverse section of the clamp and tangent screw on the line 3 3 of Fig. 1. Fig. 4 is a sectional plan view of the same, with the frame and drawing-board in section. Fig. 5 is a front view of the same, and Fig. 6 is an enlarged transverse section of part of the improvement on the line 6 6 of Fig. 1.

The improved drawing-board is provided with a suitably-constructed frame A, in the center of which is secured a metallic bearing B, engaged by a pivot 0, attached to the under side of the board D, which is circularin shape and mounted to revolve by its pivot O on the main frame A. On one end of the main frame A is formed a head E, having its outer end formed into a straight edge F for applying the T-square or other tool used in drawing.

On the top of the head E, and at the inner segmental edge thereof, is secured a quadrant Gr, extending slightly over the top of the drawing-board D, as is plainly illustrated in Figs. 1 and 6. The quadrant G is provided with graduations G and G each reading half-degrees from 0 to 90, the two sets of figures, however, being arranged in opposite directions on the inner and outer edge of the said quadrant, as is plainly shown in Fig. 1.

On top of the drawing-board D, on the edge of the same, are secured the verniers H, II, H and H located ninety degrees apart and lettered, respectively, s. e., N. E., n. w., and S. W., said verniers being graduated to read to minutes on the quadrant G. The two verniers II and H being marked with the small initials s. e. and n. w., respectively, are used in connection with the graduation marked in small figures on the quadrant G, while the two verniers II and H marked with the large initials N. E. and S. IV, respectively, are used in connection with the graduation marked in large figures on said quadrant, it being understood that the said s. e., n. w., N. E., and S. \V. are the initials of bearings in surveyingi. a, southeast, northwest, northeast, and southwest.

In order to ease the revolving motion of the drawing-board D on the frame A, a series of friction-rollers I are journaled in the frame A and are adapted to engage the under side of the drawing-board D near its outer edge, as is plainly indicated in dotted lines in Fig. 1 and in full lines in Fig. 2. In order to lock the drawing-board D in place on the main frame A and to move the drawingboard slightly, in order to adjust it to the proper reading, a device J is provided, attached on one side of the head E and provided with a frame J, fastened to the said head, as is plainly illustrated in Figs. 3 and A.

On the inner end of the frame J is formed a slot J extending radially relative to thedrawing-board and engaged by the pivot K of a lever K, formed at its inner end with a segmental offset or cam K adapted to abut against the edge of the board D. On the outer end of the lever K is formed anut K in which screws a left-hand screw N, having its bearing in the flange J of the frame J.

On the screw N are secured two cams N, engaging the inner and outer faces of the flange J so as to hold the screw-rod in place. The outer end of the screw-rod is provided with a suitable head N for conveniently turning the same, so as to move the lever K inward or outward to bring the cam end KL in or out of contact with the edge of the drawing-board D.

It is understood that in the inward and outward movement of the lever K the latters pivot or fulcrum K slides in the radially-arranged slot J of the fixed frame J The screw-rod N is mounted to slide horizontally with the lever K in a segmental slot J formed in the flange J of the frame J, as is plainly shown in Fig. 5. One end of the slot J is. formed with an enlarged recess J into which is adapted to pass the screw-rod N, and when in such a position the latter is secured in place by a set-screw O, screwing in theflangeJ In using the device the paper is fastened on the board D and the latter is turned, according to the bearings or angles to be mapped out or laid down on the paper, by turning the drawing-board so that the respective Vernier H H or H H reads on the respective graduation G or G of the quadrant G. The T- square is applied on the straight edge F of the head E to draw the proper lines according to the bearings indicated by the Vernier on the respective) scale G or G When the drawing-board D' has been turned to about the proper reading, then the operator by moving the lever K into a central position and turning the head N of the screw-rod N clamps the drawing-board D. Then by sliding the screw-rod N either to the right or left, as the case may be, he can impart a slow motion to the drawing-board D, so as to bring the exact point of the reading of the Vernier in line with the proper degree and minute. Thus it will be seen that surveys may be readily plotted on the drawing-board Without the use of protractors, triangles, straight-edges, or other tools, as in the ordinary way of plotting. Furthermore, the drawing-board D can be readily revolved, so as to suit the incoming light, to facilitate the figuring and lettering and contribute to the ease of the draftmans position. It will further be understood that when the device is used for plotting surveys the lines are all drawn from left to right and figured and lettered each time correctly with reference to the meridian, magnetic or true, as the case may be. Furthermore, the paper on the drawing-board may be changed on the board to agree with the drawings of another plot or plots, so that a number of plots may be laid out together, even if there is a variation in the different plots.

Having thus fully described my invention, I claim as new and desire to secure by Letters Patent- 1. In a drawing-board, the combination, with a stationary frame provided with a head, of a quadrant secured on the said head, a drawing-board mounted to revolve on the said frame, and verniers secured on the outer edge of the said drawing board ninety degrees apart,the said verniers readingon the graduat'ions of the said quadrant, substantially as shown and described.

2. In a drawing-board, the combination, with a stationary frame provided with a head, of a quadrant secured on the said head, a drawing-board mounted to revolve on the said frame, verniers secured on the outer edge of the said drawing-board ninety degrees apart, the said verniers reading on the graduations of the said quadrants, and a clamp and tangent screw for moving the said circular board and fastening it to the said frame, substantially as shown and described.

3. In a drawing-board, the combination, with a stationary frame provided at one end with a head having an outer straight edge and an inner segmental edge, of a quadrant secured on the segmental edge of the said head and projecting over the same, the said quadrant being provided with two graduations reading half-degrees and arranged in opposite directions, a drawing-board mounted to revolve on the said frame and concentric with the said quadrant, and verniers secured on the top of the said drawing-board ninety degrees apart, two oppositely-arranged verniers reading on the same graduation of the said quadrant, substantially as shown and described.

4. The combination, with a frame, of a circular board mounted to. rotate thereon and a horizontally swinging and longitudinallymovable' table operating and clamping lever mounted on the frame and having a round I inner end engaging the periphery of the board,

whereby the lever may be moved longitudinally to clamp the board or swing horizontally to rotate the table, substantially as set forth.

5. In a drawing-board, the combination, with a frame having a head and a drawing-board mounted to revolve on the said frame, of a clamp-frame secured on the said head and provided with aradial slot, a lever having its pivot or fulcrum engaging the said radial slot, the inner end of the said lever being adapted to engage the edge of the said circular drawing-board, and a screw mounted to turn and to slide in the said frame and screwing in the said lever, substantially as shown and described.

JUNIUS 1). MCOABE.

Witnesses:

A. D. GUY, E. D. SMITH. 

